BARTEX® is a specially heat treated, cold rolled high carbon steel. In its delivered condition, Bartex has a significantly higher tensile strength and yield to tensile ratio compared to hardened and tempered material of similar dimensions. The mechanical properties of Bartex are further enhanced by using a controlled strain aging heat treatment. Based on specific applications, strain aging process can be applied to the formed spring (as with constant force springs) or the material prior to fabrication of springs (as with power springs).
Bartex uses selected raw material with a low inclusion level, smooth and tight surface finish, and textured grain orientation resulting from heavy cold reduction and close control of metallurgical properties. This results in considerably improved fatigue properties, provided that good practices are used to control stress raisers.
Although plain carbon steels having a carbon range of 0.60% through 1.25% can be considered to make a textured material, the most suitable grade is an eutectoid plain carbon steel (carbon 80%) which is cold rolled to produce a 100% textured condition, and this is known as Bartex.
The following is some typical Bartex data:
Available thickness: 0.004 - 0.025" (.10-.64 mm)
Available width: 0.093 -12.0" (2.36-304.8 mm)
Size: 16" (406 mm) I.D. unless otherwise specified. Maximum O.D. 48" (1219 mm) unless otherwise specified.
Surface Finish: Bright cold rolled, uncoated condition.
Surface Coating: Parts made out of Bartex can be coated with metal or polymer provided the process temperature does not exceed 480°F (249°C).
Mechanical Properties: The properties vary according to the rolling direction. Material transverse to rolling direction has the maximum ductility. The material is somewhat limited for forming.
Customers must do a low temperature strain age at @464°F (240°C) for 1/2 hour for optimum spring properties.
The following typical mechanical properties are obtained after a 464°F (240°C) stress relief:
Thickness Range: Less than 0.006" (0.15 mm)
Tensile: 340-380 KSI (2346-2621 N/mm2)
Vise Break: 23 x Thickness
% Elongation: 1.0
Thickness Range: 0.0098M - 0.006" (.25 - .15 mm)
Tensile: 320-355 KSI (2205-2448 N/mm 2)
Modulus: 29-30 Million PSI
0.2%/UTS Ratio: 95-98 %
0.010% Proof Stress: 310 KSI (2138 N/mm 2)
Vise Break: Less than 22 x Thickness
15N Hardness: 15N 86 - 88
Thickness Range: 0.025" -.010" (.64-.25 mm)
Tensile: 270-330 KSI (1862-2276 N/mm 2)
%Elongation: 3 - 1
Vise Break: 14 - 20 x Thick
Ductility: Good - Fair
Consult Theis Precision Steel for your specific application.
Other Grades of Textured Material:
Textured Materials using other carbon grades, such as TRM-26 (AISI 1065), TRM-34 (AISI 1074M), TRM-54 (AISI 1095), etc. are produced by Theis. Each textured material has its own unique properties and typical product applications. Some typical data is as follows: